A GSM EDGE radio access network (GERAN) system base station may communicate with one terminal by using multiple carriers at non-contiguous frequencies. Four contiguous frames on one packet data channel (PDCH) in a PS domain on a GERAN constitute one radio block, and data encoding and decoding are performed in a unit of radio block. In a downlink multicarrier (DLMC) feature, due to a limitation of a maximum carrier frequency spacing supported by a terminal, a case in which data on some carriers cannot be received in each radio block period may occur. In this case, a carrier selection method may be used, so that a transmit end and a receiving end perform information transmission by using a uniform carrier. For example, the transmit end may select some carriers of multiple carriers for sending, and correspondingly, the receiving end listens to a downlink radio block only on the some carriers.
In the prior art, a carrier selection method used is a brute force method, in which all carrier selection solutions are enumerated to find a solution that has a largest quantity of carriers and meets a limitation of a maximum carrier frequency spacing supported by a terminal. The brute force method is equivalent to finding a maximal complete subgraph of an undirected graph, which has extremely high calculation complexity.